Startech.com PEX1S1P952 Parallel PCI Express Combo Card User Manual

StarTech.com PEX1S1P952 Parallel PCI Express Combo Card Manual

Introduction: Add Serial and Parallel Ports to a PCI Express Computer

The startech.com PEX1S1P952 Parallel PCI Express Combo Card adds one RS232 serial port and one IEEE 1284-compatible parallel port to a desktop computer through an available PCI Express slot. It is designed for systems that need to connect legacy equipment such as industrial controllers, receipt printers, label printers, scientific instruments, CNC machinery, scanners, and other serial or parallel peripherals.

Unlike older expansion cards that depend on a legacy PCI bus, this native PCI Express adapter uses a single-chip design based on the PLX OXPCIe952 chipset. The card supports standard and low-profile installations, making it suitable for many full-size desktop computers and compact workstations with compatible PCIe expansion slots.

The serial interface uses a male DB9 connector and supports RS232 communication at data rates up to 115.2 Kbps. The female DB25 parallel connector supports SPP, EPP, and ECP operating modes with transfer rates up to 1.5 Mbps. A 128-byte FIFO buffer for each transmitter and receiver helps improve data handling during sustained communication.

This PCIe serial parallel combo card is especially useful for organizations maintaining dependable legacy hardware instead of replacing equipment with newer USB-based alternatives. It can also help technicians configure test benches, service older machines, or connect specialized devices that require conventional COM and LPT interfaces.

Specifications and Technical Features

• Product type: Native PCI Express serial and parallel combo expansion card
• Bus interface: PCI Express, revision 1.1, one lane
• Chipset: PLX OXPCIe952
• External connectors: One male DB9 serial connector and one female DB25 parallel connector
• Internal power connector: One LP4 Molex male connector
• Serial standard: RS232
• Serial transfer rate: Up to 115.2 Kbps
• Parallel modes: SPP, EPP, and ECP
• Parallel transfer rate: Up to 1.5 Mbps
• Serial data formats: Five, six, seven, eight, or nine data bits
• Parity options: None, even, odd, mark, and space
• FIFO buffering: 128-byte transmitter and receiver buffers
• Form factor: Full-profile and low-profile installation support
• Serial power feature: Selectable power output on serial port pin 9
• Flow control: Programmable XON/XOFF and automatic in-band flow control

How to Install the PEX1S1P952 PCI Express Serial Parallel Card

1. Shut down the computer, turn off connected equipment, unplug the power cable, and disconnect external peripherals.
2. Remove the computer case cover and locate an available PCI Express slot. Confirm that the slot and rear opening accommodate the selected full-profile or low-profile bracket.
3. Remove the corresponding expansion-slot cover. Avoid touching the card’s gold contacts and hold the adapter by its edges.
4. Insert the card firmly into the PCIe slot, secure the bracket with the case screw, and connect the internal LP4 Molex power lead if required by the installation.
5. Reassemble the case, reconnect the computer, and attach the RS232 or DB25 peripheral after the operating system loads.
6. Install the appropriate serial and parallel drivers from the StarTech.com driver package. If automatic installation does not start, use Device Manager and manually select the serial driver file oxserleg.inf and the parallel driver file OxMf.inf or OxPCIeMf.inf.
7. Verify the new COM and LPT entries in Device Manager. Configure the COM port number, baud rate, parity, data bits, stop bits, and flow control to match the connected equipment.

Safety warning: Never install or remove the card while the computer is powered. Check peripheral voltage requirements before using serial pin-9 power, and do not force a connector into place.

Troubleshooting the StarTech.com PEX1S1P952

• Card is not detected: Power off the computer and reseat the adapter. Try another compatible PCI Express slot, confirm that the LP4 power connection is secure, and check whether the card appears in Device Manager.
• Yellow exclamation mark or “PCI Serial Port” entry: Install the correct operating-system driver manually through Device Manager. Browse to the extracted driver folder and select the appropriate INF file.
• Serial device does not communicate: Match the baud rate, parity, data bits, stop bits, and flow-control settings on both devices. Confirm that the cable uses the correct straight-through or null-modem wiring.
• Parallel printer or controller is unavailable: Test SPP, EPP, and ECP modes in the operating system or application. Confirm that the software is using the assigned LPT port.
• Intermittent data loss: Use a suitable, undamaged cable, reduce the communication speed if supported by the equipment, and verify flow-control settings.
• Legacy software cannot find the port: Reassign the COM or LPT port to the number expected by the application, then restart the software.

Before contacting support, record the computer model, operating system, PCIe slot used, Device Manager status, driver version, and connected peripheral. For driver updates, manuals, compatibility information, and warranty assistance, use the StarTech.com Support, Drivers & Downloads, and Contact Support areas and search for product ID PEX1S1P952.

Pros and Cons of the PEX1S1P952 PCIe Combo Card

Advantages

• Two legacy interfaces in one adapter: Provides both RS232 serial and DB25 parallel connectivity without occupying separate expansion slots.
• Native PCI Express design: Works through a PCIe slot rather than requiring an older conventional PCI bus.
• Broad parallel compatibility: SPP, EPP, and ECP modes support common printer and industrial-device configurations.
• Useful buffering: 128-byte transmit and receive FIFOs help maintain reliable serial data flow.
• Flexible installation: Full-profile and low-profile support suits many desktop chassis designs.
• Practical legacy replacement: A strong fit for businesses that must continue using specialized RS232 equipment or parallel hardware.

Limitations

• Legacy-focused performance: The serial interface is limited to 115.2 Kbps, so it is not intended for high-speed modern data transfer.
• Desktop expansion required: The card needs an available compatible PCIe slot and is not designed for laptops or small computers without expansion access.
• Driver dependence: Older operating systems and specialized applications may require manual port assignment or driver configuration.
• Specialized use case: Users needing only USB connectivity, multiple serial ports, or modern networking features may need a different adapter category.

The startech.com PEX1S1P952 Parallel PCI Express Combo Card best suits technicians, industrial users, and desktop owners who need dependable serial and parallel connectivity in one PCIe expansion card.